When you walk across the carpet and touch a metal doorknob, you create a spark. This occurs because _____________

) An instructor gives his class a set of 18 problems with the information that the next quiz will consist of a random selection

RSB [31]

Answer:

The probability the he or she will answer correctly is 1.5%

Step-by-step explanation:

In all, there are 18 problems. In this question, the order of which the problems are sorted for the quiz makes no difference. For example, if the question A of the quiz is P1 and question B P2, and question A P2 and question B P1, it is the same thing.

There are 18 problems and 9 are going to be selected. So, there is going to be a combination of 9 elements from a set of 18 elements.

A combination of n elements from a set of m objects has the following formula:

$C_{(m,n)} = \frac{m!}{n!(m-n)!}$

In this question, m = 18, n = 9. So the total number of possibilities is:

$T_{p} = C_{(18,9)} = \frac{18!}{9!(18-9)!} = 48620$

Now we have to calculate the number of desired outcomes. This number is a combination of 9 elements from a set of 13 elements(13 is the number of problems that the student has figured out how to do).

Now, m = 13, n = 9. The number of desired possibilities is:

$D_{p} = C_{(13,9)} = \frac{13!}{9!(13-9)!} = 715$

The probability is the number of desired possibilities divided by the number of total possibilities. So

$P = \frac{715}{48620} = 0.015 = 1.5%$

The probability the he or she will answer correctly is 1.5%

3 0

3 years ago

You wonder how many cars there are in your area. You call up the Ford dealership and ask how many Fords they’ve sold. They repor

SVETLANKA909090 [29]

If we take 1200 as the 100%, how much percentage is 700 of it?

well $\bf \begin{array}{ccllll}
amount&\%\\
\textendash\textendash\textendash\textendash\textendash\textendash&\textendash\textendash\textendash\textendash\textendash\textendash\\
1200&100\\
700&x
\end{array}\implies \cfrac{1200}{700}=\cfrac{100}{x}\implies x=\cfrac{700\cdot 100}{1200}
\\\\\\
x=\cfrac{175}{3}$

so, (175/3)% or roughly 58.3%

now, how much is (175/3)% of 15000 ?
well, if we take 15000 as the 100%
then $\bf \begin{array}{ccllll}
amount&\%\\
\textendash\textendash\textendash\textendash\textendash\textendash&\textendash\textendash\textendash\textendash\textendash\textendash\\
15000&100\\
x&\frac{175}{3}
\end{array}\implies \cfrac{15000}{x}=\cfrac{100}{\frac{175}{3}}
\\\\\\
\cfrac{15000\cdot \frac{175}{3}}{100}=x\implies \cfrac{5000\cdot 175}{100}=x$

6 0

3 years ago

Which equation is quadratic in form?

mixas84 [53]

Answer:

I think it's the first one... but I'm not pretty sure.

4 0

3 years ago

Read 2 more answers

The point (5, -2) is rotated 90° about the origin. Its image is

Nadya [2.5K]

Answer:

(2,5)

Step-by-step explanation:

The rule to 90 degrees about the origin is (x,y) to (-y,x). You basically switch the values of y and x but remember the value of y is negative. The value of y is -2 so -2 is now 2 since the rule changed the sign (-2×-y=2) and 5 isnt affected except it is the x value. Just know that since they r switched, x is now 2 and y is 5 when rotated 90 degrees about the origin.

8 0

3 years ago

Write what the expressions below best represent within the context of the word problem.

Brilliant_brown [7]

X=2 NICKELS.

3*2=6 QUARTERS.

PROOF:

.25*6+.05*2=1.60

1.50+.10=1.60

1.60=1.60

3 0

3 years ago

When you walk across the carpet and touch a metal doorknob, you create a spark. This occurs because ______________.